yeah... i tried entering using "guest" as the username and password but still couldn't,i also have a question... when they say free in reality they mean "we let you play but we want you to buy the cards" right?

I'm not sure what you mean. The content of the games that are available to the public are whatever the developer makes available. There's no stipulation that the submission must be made available to the public at all. Whether or not a game is free (and their billing policies) has nothing to do with IGF.

The tower defense games are really no more copycats than any game is a copy of other games in its genre. It's just that it's a relatively new genre so gives off the impression that they're all the same. But to an outsider all RTS games or all platformers or all FPS games also look like clones of each other.

I think they differ in almost everything, if you've played enough of them.

They all have things to shoot that (usually) don't shoot back, things that shoot, and the things that shoot are (usually) stationary and (usually) can be upgraded. But that's where the similarities end. They differ in everything besides those.

Platformers all have platforms and (virtually always anyway) jumping, with the purpose to get to a particular place or find or collect something, and they (usually) have enemies, and there's (usually) a way to kill those enemies. But they differ in everything besides those.

RTS games all have battles between armies a bunch of different kinds of units that can be moved around and buildings that build units and resources which have to be managed and (usually) have to be mined by your units. But they differ in everything besides those.

And so on, every genre has core similarities but there's a lot of variation possible in that genre if you play enough of them.

I think when platformers were first coming out everyone saw them as Pitfall or Mario clones, and when RTS games were first coming out everyone saw them as Dune 2 or Warcraft clones.

I'm not saying there aren't a lot of derivative tower defense games, there are, a lot of them are too similar to Warcraft 3 mods, even using sound effects and such from Warcraft. But I'm saying that just because a game is in the tower defense genre doesn't mean it's a clone; not every platformer is a clone of Mario.

Thanks, but that didn't clear it up. It didn't say what the differences are between them. Take the two most notably different Tower Defence games, and a third one inbetween, and see where the different lays: a gimmick or a core difference. That's what I want to know.

Immortal Defense, my game, has a space setting, short levels of a few minutes each, carry-over of funds between levels, and a mouse that shoots. It's also very story-centric, with a plot and characters, whereas most TD games don't have a story at all.

Desktop Tower Defense, also in the IGF, has a desktop (literally, someone's desk) setting, and no set paths so you have to arrange the towers in a "maze" for the enemies, only a single level but many different modes of play.

Master of Defense, another shareware TD game, is in 3D as opposed to those two 2D games, it has a fantasy setting of magic and castles, and a more traditionally Warcraft-like gameplay of about 8 or so fairly long levels.

To add a bit more, they differ in strategy: some are more fast-paced than others, some rely more on reaction time, others are more cerebral like chess; the towers also shoot differently and have different special features, the variety of enemies and bosses are different, etc.

Some have better gameplay than others; in some there are easy ways to always win and you don't have to change your strategy once you've found the one best way, in others the best way varies significantly by situation and there is never always one best way.